List<Action> actions = new List<Action>();
for(var count=0; count<10; count++)
{
    actions.Add(() => Console.WriteLine(count));
}
foreach(var action in actions)
{
    action();
}

var s1 = string.Format("{0}{1}", "abc", "cba");
var s2 = "abc" + "cba";
var s3 = "abccba";
 
Console.WriteLine(s1 == s2);
Console.WriteLine((object)s1==(object)s2);
Console.WriteLine(s2==s3);
Console.WriteLine((object)s2==(object)s3);

public class A
{
    public virtual void Print1()
    {
        Console.Write("A");
    }
    public void Print2()
    {
        Console.Write("A");
    }
}
public class B: A
{
    public override void Print1()
    {
        Console.Write("B");
    }
}
public class C : B
{
    new public void Print2()
    {
        Console.Write("C");
    }
}

var c = new C();
A a = c;
 
a.Print2();
a.Print1();
c.Print2();

class Program
    {
        static void Main(string[] args)
        {
            BitArray ba1 = new BitArray(4);
            BitArray ba2 = new BitArray(4);
            ba1.SetAll(true);
            ba2.SetAll(false);
            ba1.Set(2, false);
            ba2.Set(3, true);
            Console.WriteLine(ba1.And(ba2).Get(2));
        }
    }

class Super{
        static Super(){
            Console.WriteLine("Salom");
        }
        public Super(){
            Console.WriteLine("C#");
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            new Super();
        }
    }

class Program
    {
        static void Main(string[] args)
        {
            int x = 9;
            int y = x + x * x / x * x;
            Console.WriteLine(y);
        }
    }

class Program
    {
        static void Main(string[] args)
        {
            HashSet<string> h = new HashSet<string>();
            h.Add("0");
            h.Add("1");
            h.Add("0");
            h.Add("1");
            Console.WriteLine(h.Count);
        }
    }